1. Field of the Invention
The present invention relates generally to the recovery of water from an underground source through the use of a reciprocating pump system. The present invention relates more specifically to an improved water pumping system adapted to be driven by a windmill that utilizes an air lift fluid pump for generating a flow of water to the surface.
2. Description of the Related Art
Water pumping windmills may be found on farms and ranches worldwide and provide critical water supply for domestic and livestock use, especially in areas where electrical and fuel driven pumps are not practical. The type of technology associated with these windmill water pumps has enjoyed continuous use since the late 19th Century and may be generally illustrated by U.S. Pat. No. 1,632,188 assigned to the Dempster Mill Manufacturing Company (1927). This type of windmill pumps water by means of a positive displacement, reciprocating pump, submerged below the static water level of a drilled well. The pump is conventionally connected and supported by a water discharge pipe which leads to the surface and a reservoir for the water. The pump is driven by a reciprocating rod, typically made of wood or fiberglass, which reaches down from the windmill""s transmission to the pump through the discharge pipe.
It is typical in reciprocating water pumps of this type to utilize a barrel or cylinder within which a piston is moved in a reciprocating motion by the pump rod. Both the piston and the bottom of the pump barrel incorporate check valves that allow water to flow only in the upper direction. The check valve at the bottom of the cylinder is commonly called the foot valve, while the valve in the piston is commonly called the lift valve. When the piston is lifted by the pump rod attached to the surface windmill, the lift valve closes and the piston lifts the entire column of water above it until water overflows out of the discharge pipe at the surface. At the same time a slight suction is formed under the piston causing the foot valve to open and water to flow in under the piston. During the next half of the cycle the piston moves down causing the foot valve to close and the lift valve to open such that water flows through the piston into a position to be lifted during the next half cycle.
Water flow valves, such as those described above, must be periodically replaced. The lift valve, which is typically made of leather or rubber, eventually wears due to particles of sand or earth in the water. Other check valves involved with the system also have finite useful lives and must be replaced on a regular basis. Replacement typically involves the removal of the pump rod, discharge pipe and pump by lifting the entire assembly up from the drilled well in order to access the valves. Such replacement efforts involve considerable labor and expense and greatly affect the down time of the windmill pumping system.
Obviously many efforts have been made in the past to replace the windmill pumping system powered by electrical motors and internal combustion engines. The present concern relates only to such efforts that have sought to improve upon wind driven pumping systems. One effort in the past is described in U.S. Pat. No. 3,367,281 issued to Gray on Feb. 6, 1968 entitled APPARATUS FOR PUMPING WATER FROM WELLS USING WIND POWER. The Gray patent discloses a water pumping device in which compressed air is generated by a windmill, stored in a tank, controlled through a pressure regulator, and delivered to a displacement type water pump. This invention, although not overly complex, is not directly adaptable to the typical windmill structure. The Gray disclosure describes a down stroke of a windmill pump rod as the compression stroke which does not lend itself well to application in conjunction with typical windmills that are designed to apply force and power on the upstroke of the pump rod. The pump rod conventionally made of wood would likely snap if used to compress air on the down stroke. The Gray invention also utilizes solenoid valves that are electrically controlled to effectuate the air compression cycle. Such electrically controlled valves are typically not practical in remote windmill locations. Finally, the Gray invention further requires the use of an air hold-up means and a pressure regulator.
U.S. Pat. Nos. 4,385,871 and 4,358,250 provide further examples of inventions generally related to the conversion of wind energy into compressed air for the purpose of water pumping. These earlier efforts, however, also do not address an appropriate adaptation of the air compressing mechanism to the typical windmill structure or to the utilization of the same in conjunction with an air injection type water pump.
It is therefore an object of the present invention to provide a water pumping system that is driven by a reciprocating windmill pump rod that is inexpensive to produce, install, maintain and operate.
It is a further object of the present invention to provide a water pumping system that may be retrofit onto existing reciprocating windmill structures and thereby replace the reciprocating water pump system utilized thereon.
It is yet another object of the present invention to provide an air lift water pumping system that retrofits to existing windmill structures and eliminates the heretofore required maintenance efforts associated with windmill well pumps.
It is a further object of the present invention to provide an improved air lift water well pumping system that may be retrofit onto existing windmill structures and which utilizes the upstroke as the power stroke in providing compressed air to an airlift pump positioned below the water level under the ground.
In fulfillment of these and other objectives, the present invention provides a system for pumping water from a well drilled into an underground water source that is operable in association with the windmill having a tower frame, a wind driven turbine, and a reciprocating pump shaft operably connected to the turbine. The system includes an air pump mechanically linked to the reciprocating pump shaft of the windmill and operable by the direct reciprocating motion of the shaft. The air pump is positioned within the windmill tower frame in line with the shaft and is held stationary with respect to the ground. The air pump operates through the reciprocating motion of the windmill shaft and delivers a flow of compressed air from an outlet port. An air conduit is connected to the outlet port and is directed into the well down to a point below the water level within the well. An air lift fluid pump is positioned within the well and comprises a fluid conduit with a first end positioned below the ground within the water table for receiving a flow of water there from, and a second end that extends above the ground for delivering a flow of water thereto. The air lift fluid pump comprises a submerged mixing chamber wherein compressed air received from the air conduit from the surface is injected into the mixing chamber forming a buoyant air-water mixture. This buoyant mixture flows towards the surface which in turn draws water up through the fluid conduit to the surface.